Silicon microphone

Abstract

One of the main objects of the present invention is to provide a silicon microphone that is reasonably designed and can effectively improve electroacoustic performance. To achieve the above-mentioned objects, the present invention provides a silicon microphone including a substrate with a back cavity; and a capacitor system attached to and insulated from the substrate. The capacitor system includes a diaphragm and a back plate spaced from the diaphragm. At least one through hole is formed in the back plate. The diaphragm includes a vibration part in a middle thereof and a fixed part surrounding and spaced from the vibration part by a first slit. An orthographic projection of the vibration part on the substrate partially overlaps with the substrate thereby forming a second slit between the vibration part and the substrate and communicating with the first slit and the back cavity, respectively.

What is claimed is: 
     
         1 . A silicon microphone including:
 a substrate with a back cavity;   a capacitor system attached to and insulated from the substrate, including a diaphragm and a back plate spaced from the diaphragm;   at least one through hole formed in the back plate; wherein   the diaphragm includes a vibration part in a middle thereof and a fixed part surrounding and spaced from the vibration part by a first slit;   an orthographic projection of the vibration part on the substrate partially overlaps with the substrate thereby forming a second slit between the vibration part and the substrate and communicating with the first slit and the back cavity, respectively.   
     
     
         2 . The silicon microphone as described in  claim 1 , wherein, a sidewall of the back cavity is closer to a center of the back cavity than the first slit, for forming an overlapping area between the orthographic projection of the vibration part and the substrate. 
     
     
         3 . The silicon microphone as described in  claim 1  including a plurality of the at least one through holes, wherein an orthographic projection of the first slit on the back plate falls on an outer side of the outermost through hole. 
     
     
         4 . The silicon microphone as described in  claim 1 , wherein, a distance between a part of the back plate corresponding to the first slit and the diaphragm, is smaller than a distance between other parts of the back plate and the diaphragm. 
     
     
         5 . The silicon microphone as described in  claim 1 , wherein, a distance between a part of the substrate corresponding to the first slit and the diaphragm is smaller than a distance between other parts of the substrate and the diaphragm. 
     
     
         6 . The silicon microphone as described in  claim 1 , wherein, an area where the orthographic projection of the vibration part on the substrate overlaps the substrate is covered by an anti-absorption film structure. 
     
     
         7 . The silicon microphone as described in  claim 6 , wherein, the anti-absorption film structure includes a recess formed in a side of the vibration part facing the substrate. 
     
     
         8 . The silicon microphone as described in  claim 6 , wherein, the anti-absorption film structure includes a recess formed in a side of the substrate facing the vibration part.